The fall of a meteorite at Aegos Potami and record of a comet passing close to Earth in the 5th century BC

Aegos Potami, a name meaning in Greek ‘Rivers’ (=Potami) ‘of the Goat’ (=Aega) – although the Greek prefix ‘aeg-‘ means a place generally near water -, was a stream with an ancient small town built next to its estuary on the eastern shore of the Gallipoli Peninsula in Eastern Thrace, opposite Lampsacus and Avydus.

On the shore of Aegos Potami in the autumn of 405 BC the Athenian and the Spartan fleets faced each other, and the Spartan Admiral, Lysander, succeeded in conquering the Athenian fleet. The catastrophe was complete for the Athenians: 170 ships were seized by the Spartans and 3000 men were captured and then killed. This disastrous encounter virtually signified the end of the great Peloponnesian War. The Spartans, under King Agis and Lysander, then besieged Athens, which was finally forced to capitulate under humiliating terms.

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The 60-tonne, 2.7-metre long Hoba meteorite in Namibia is the largest known intact meteorite

Plutarch mentions that ancient writers were of the opinion that this catastrophe had been foretold by the fall of a very large meteorite at Aegos Potami in 467/6 BC. Furthermore, according to Pliny the Elder (AD 23-79), Plutarch (AD 45-120), Philostratus (2nd century AD), Diogenes Laertius (3rd century AD), and other authors, the philosopher Anaxagoras even predicted the fall of this meteorite. For example, Philostratos (1912:9) writes: “… we might also accuse Anaxagoras because of the many things which he foretold. [including] … that day would be turned into night, and stones would be discharged from heaven round Aegos Potami, and of how his predictions were fulfilled.”

Anaxagoras certainly was a remarkable man, and he was very knowledgeable about astronomy. He held the view that meteorites were celestial bodies that from time to time happened to fall to Earth, and he also held equally progressive views about meteors and the composition of stars. Because of his views, Anaxagoras was unpopular in Athens where he almost lost his life accused of atheism.

In his Lives of Lysander and Sulla. Plutarch (AD 45-120) states:

There were some who declared lhat the Dioscuri (Castor and Pollux) appeared as twin stars on either side of Lysander’s ship just as he was sailing out of the rudder-sweeps. And some say that the falling of the stone was also a portent of this disaster; for, according to the common belief, a huge stone had fallen from heaven at Aegos Potami, and it is shown to this day by the Cherronesites, who hold it in reverence. It is said that Anaxagoras had predicted that if the heavenly bodies would be loosened by some slip or shake, one of them might be torn away, and might plunge and fall down to earth, and he said that none of the stars remained in its original position: because, as they are compact as stones and heavy, they shine due to friction with the revolving aether, and they are forced along in fixed orbits by the whirling impulse which gave them their circular motion. and this was what prevented them from falling to our earth in the first place. when the cold and heavy bodies were separated from the whole universal matter …

But there is a more plausible opinion than this, and its advocates hold that shooting stars are not a flow or emanation of aetherical fire, which the lower air quenches at the very moment of its kindling, nor are they an ignition and blazing up or a quantity of lower air which has made its escape into the upper regions: but they are plunging and falling heavenly bodies, carried out of their course by some relaxation in the tension of their circular motion and falling. not upon the inhabited region of the earth, but for the most part outside of it and into the great sea; and this is the reason why they are not noticed…

However, the theory of Anaxagoras is supported by Daïmachus in his treatise Peri Eusebias (On Religion): he says that prior to the fall of the stone, for seventy-five days continually, there was seen in the heavens a huge fiery body similar to a flaming cloud, not resting in one place but moving along with intricate and irregular motions. so that fiery fragments broken from it by its plunging and erratic course were carried in all directions and flashed fire, just as shooting stars do. But when it had fallen in that part of the Earth and the inhabitants, after recovering from their fear and amazement, were assembled around it, no action of fire was seen, nor even so much as trace thereof, but a stone lying there, of large size, it is true, but one which bore almost no proportion at all to the fiery mass seen in the heavens. Well, then, that Daïmachus must have indulgent readers, is clear; but if his story is true, he utterly refutes those who affirm that a rock, which winds and tempests had torn from some mountain top, was caught up and borne along like a spinning top, and that at the point where the whirling impetus given to it first relaxed and ceased, there it plunged and fell. Unless, indeed, what was seen in the heavens for many days was really fire, the quenching and extinction of which produced a change in the air resulting in unusually violent winds and agitation, and these brought about the plunge of the stone. However, the minute discussion of this subject belongs to another kind of writing.” (Plutarch, 1916;260-265)

According to Pliny (1938, II: 149) the meteorite fall occurred in the year 467/6 BC, while Aristotle (384-22 BC) records that the event took place during daylight hours and that a comet was visible in the evening sky at the time: “…when the stone fell from the air at Aegos Potami it had been lifted by the wind and fell during the daytime; and its fall coincided with the appearance of a comet in the west.” (Aristotle, 1952:55). In another account, Aristotle provides more details:

On the occasion when the (meteoric) stone fell from the air at Aegos Potami, it was caught up by a wind and was hurled down in the course of a day; and at that time too a comet appeared from the beginning of the evening. Again, at the lime of the great comet (373/2 BC) the winter was dry and arctic, and the tidal wave was caused by the clashing of contrary winds; for in the bay the north wind prevailed, while outside it a strong south wind blew, Further, during the archonship of Nicomachus at Athens (341/0 BC) a comet was seen for a few days in the neighbourhood of the equinoctial circle; it was at the time of this comet, which did not rise with the beginning of the evening, that the great gale at Corinth occurred” (Heath, 1981:246).

These accounts by Aristotle appear to be the earliest mention of the Aegos Potami Meteorite by any writer whose works has survived, while the second century BC doxographer, Aetius, also reports this event:

Diogenes says that the stars are like pumice stones, and he considers them as pores through which the world breathes; and that they are red-hot. In addition to the visible stars, invisible stones also wander through the heavens, having no name, They frequently fall on Earth and their fire gets extinguished, like the stony star which fell in flames at Aegos Potami” (Aetius, 1879:342).

Diogenes was a contemporary of Anaxagoras.

Pliny the Elder (AD 23-79) reports the same event in his Naturalis Historia, and he also mentions a meteorite that fell at Avydus, again apparently after a prediction by Anaxagoras. An English translation of the relevant passage reads:

The Greeks say that Anaxagoras of Clazomenes succeeded during the second year of the 78th Olympiad [467/6 BC] with his knowledge in astronomical literature to predict that some days later a stone from the Sun would fall, and this happened during the daytime at the area of Aegos Potami of Thrace – and this stone can be viewed even today, having the size of a chariot and brown color – when a comet was shining during the nights. If one believes in this prediction, he must at the same time accept that the supernatural abilities of Anaxagoras consisted of an even greater miracle, that our understanding of nature is zero and everything is in confusion if it is credible that either the Sun itself is a stone or it ever used to have a stone inside it. Yet it is not doubted that stones do fall frequently. For this reason, in the sports center of Avydus they still worship today a stone, medium-sized to be fair, for which it is said that Anaxagoras had again predicted its falling at the middle of the Earth” (Pliny, 1938:284).

Pliny also describes the Aegos Potami Meteorite as “…the size of a wagon and black in
colour.” (cited in Brown, 1973:153).

Apart from Pliny the Elder’s reference to its size and colour, there are no descriptions of the appearance or physical properties of the Aegos Potami Meteorite, but its brown or black colour suggests oxidation and that it was more likely an iron meteorite rather than a stony or stony-iron. This view is also supported by its size, for large iron meteorites are more commonly found intact, whereas stony meteoroids often disintegrate prior to impact.

If the Aegos Potami Meteorite really was of chariot- or wagon-like proportions, then it would have weighed an impressive several tons.

Although the fall of the Aegos Potami Meteorite is one of the most comprehensive that has been documented in the early literature, reference to it is surprisingly rare in books on meteorites or astronomy (but for some exceptions see Bagnall, 1991:1; Brown, 1973:153; Flammarion, 1955:395; Moore, 1971:1).

(Source: The fall of a meteorite at Aegos Potami in 467/6 BC”, by E. Th. Theodossiou et al.)

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Hale-Bopp comet as seen from the Earth (1997)

Research-Selection for NovoScriptorium: Isidoros Aggelos

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